Historically endurance training has focused on the central adaptations (cardiovascular) and paid scant regard for peripheral adaptations (neuromuscular).
Metabolic conditioning is far more complex than simply trying to develop lungs like dustbin liners.
The late Mel Siff put it prety well when he said
'the development of endurance is associated with functional specialisation of the skeletal muscles, particulalry the enhancement of their strength and oxidative qualities, rather than improvement of cardiovascular ability.'
Modern coaches need to recognise the importance of developing programmes that improve both central and peripheral adaptations.
One of the best places to start is with the work of Martin Buchheit, one of the sharpest minds on energy system development that I've come across in recent years.
His work is well worth a look.